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Cryptography · Module 5 of 10

Password storage

Store passwords safely with slow, salted hashing.

📖 Key ideas

  1. Never store passwords in plain text or with reversible encryption.
  2. Use password hashing algorithms: Argon2, bcrypt, scrypt, PBKDF2.
  3. A salt is a random value added per password to make hashes unique.
  4. Slow hashing makes guessing expensive.
  5. Encourage long passphrases and MFA.
💡 Real-life example: Salting passwords is giving each person's fingerprint a unique smudge so two identical passwords look different.
SaltRandom value added before hashing
bcryptSlow password hashing algorithm
Argon2Modern password hashing winner
Work factorTunable cost of hashing